Security systems which provide some degree of control of the ingress to and egress from enclosed or secure areas are known. Generally, there are two known approaches in such security systems. One approach is to physically harden the entry doors (and their associated hardware, i.e. locks and hinges) leading into the secure area. The objective is to increase the amount of time that it takes to penetrate the entry doors at least to that of the penetrability of the surfaces adjacent to the doors, i.e. the walls, ceiling, and floor. The rationale is to insure that doors which are provided for authorized ingress do not facilitate unauthorized entry by force.
The second approach comprises using doors adapted to be locked and unlocked by a mechanism responsive to a single event. For example, the event triggering the mechanism may be the turn of a key, the entry of a code, or the actuation of a switch by one having authority to lock and unlock the door, e.g. a security guard. Security effectiveness can be increased with "anti-passback" or "anti-piggyback" enhancements in the mechanism, whereby the mechanism unlocks the door in response to its recognition of credentials personal to authorized persons, such as weight or a personal key or code. A time delay may also be included so that the personal key or code cannot be used more than once during a specific time period.
In high security applications, the second approach is typically implemented using a "Two Person Rule". The Two Person Rule is based on the principle that insider adversarial activity is usually committed alone. Thus, when the Two Person Rule is implemented, a mechanism is provided for locking and unlocking the doors that can be activated only by two persons acting together, thereby significantly reducing the likelihood that the opening of the door is for adversarial purposes.
Doors used in accordance with the latter system may be part of a vestibule through which persons must pass in order to enter the secure area. By locking the doors to the vestibule, the vestibule can operate as a man trap in the event adversarial activity is suspected. For example, the vestibule may have a time delay that provides security personnel with time to examine an individual who seeks to leave the secure area. The time delay is triggered by the opening and closing of one of the doors, indicating that the individual seeking egress has entered the vestibule. Before the expiration of the time delay, however, the security person accesses the vestibule to view the individual or individuals and, among other things, to confirm that the correct number of individuals are present. If adversarial activity is suspected, the security person actuates an emergency switch or the like which locks the individual or individuals in the vestibule. Otherwise, upon expiration of the time delay, the other vestibule door opens, enabling the individual to leave.
Regardless of the type of security system used, there are always safety concerns regarding persons within the secure area who must be able to escape in the event of catastrophic events such as fires, explosions, etc. These safety concerns typically are addressed by providing secure entry doors with emergency panic opening features so that insiders may exit in the event of an emergency. Also, either in addition to or in lieu of panic opening features on secure entry doors, one or more separate emergency "panic opening" or "crash out" doors can be provided to allow insiders to exit at any time.
Although such panic opening doors are nearly foolproof in safeguarding the emergency escape of those in secure areas, they present a serious security risk. Where such panic opening doors are provided, the security system may be entirely defeated when an adversarial insider, who presumably is authorized to be within the secure area, opens the panic opening door to make an unauthorized exit or to admit an unauthorized person. Such insiders potentially include disgruntled employees, psychotics and criminals who have obtained authorization to be present in the secure area through fraud or deceit. Prior security systems fail to satisfactorily address this problem.
Accordingly, there is a need in the art for a security system that controls the ingress to and egress from a secure area, and that also addresses the problem of insider adversarial activity, all without impairing the ability of those in the secure area to escape when an by emergency arises.